<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>变量与常量</title>
</head>
<body>
    <script>
        var a = 1;
        a=6.6;
        a=false;
        console.log(a);
        var a = 'hello';
        console.log(a);

        let x = 1;
        x= 6.6;
        console.log(x);

        const y = 1;
        console.log(y);
    //     常量的值不允许被修改
    </script>

</body>
</html>